I wanted to look further into the phonograph. The one he passed around was a cylinder phonograph and it stood out to me as something I would remember from that class. 1899 the phono graph or also called the gramophone or record player was introduced in 1877 was used by the vibration of sound and waveforms that were recorded as corresponding groves engraved or impressed into a surface of a rotating disk or cylinder. It was rotated while it played back the groobe to vibrate it and reproduce recorded sound. The motions were converted through the stylus into analogous electrical signal by a transducer called a pickup or cartridge. And amplified through a loudspeaker.
Thomas Edison Emile Berliner and Eldridge R. Johnson are all credited for this invention.
“Edison Film and Sound: The History of the Edison Cylinder Phonograph.” Edison Film and Sound: The History of the Edison Cylinder Phonograph. N.p., n.d. Web. 09 Sept. 2014. <http://memory.loc.gov/ammem/edhtml/edcyldr.html>.